Treatment of clays



2,761,893 TREATMENT OF CLAYS William E. Brown, Gibsonia, .Pa., assignor to Gulf Research & Development Company Pit'tSburgh, Pa., a corporation'of Delaware Application stance. is, i954, Serial No. 469,862

19 Claims. erase- .55)

No Drawing.

swe lling-and/or dispersion, with subseq'uent loss of permeability and reduction. in mechanical strength, for the purpose of maintaining and/or restoring the permeability to fluids of such bodies and rendering them stable toward disruption by mechanical and/or che'r'nical forces.

Clay-containing bodies often aresubstantially impermeable or have a low permeability-to .fiuidsor lose some or all of the .permeabilitythey may possess when they are subjected to the action of fliquids su'chjaslwater, certain brines, emulsions containing waterv or certain brines, etc. Treatment of such clay bodies in acc ordance with the process of this invention will render them permeable, prevent a reduction in fiuid permeability andlorf-res'tore fluid permeability to those claybodies in which it has been lost. As a result of the treatment the resistanceof the clay bodies to mechanical and hemical disintegra tion will also be substantiallyinclre ed'. f,, 1 The clay or clay-like materialswhichcan be treated in accordance with my invention can include any natural geologic formations or artificial formations such as railroad or highway embankments, road beds and road surfaces, automobile parking areas, areasfor outdoor sports, storage areas, military installationafetc. Included also among the, materials which can betreated to improve or maintain their permeability .and theirphysical and/or chemical stability are manufactured. articles containing clays or clay-like materials. ,As an example, 'but without being limited thereto, this process ca jbe employed to treat articles cast, extruded or otherwise formed from clay to increase their mechanical strength ,prior to and/or after firing. I h

The process of this invention has particular applicability in the treatment of natural geologic formations for the purpose of preventing -or correcting the loss in permeability thereof caused by swelling and/ordisPersing, of the clay contained therein, preserving the approximate geometry of the grains of the formations, maintaining the pore distribution of the formation and firming the formation in the processof creating the borehole, e. g., by the tion if it .is uncemented or poorly cemented. "More specitically, this invention is especially advantageous in the treatment of a clay-containing formation adjacent a borehole in wells in order to -increase,mai ntainand/ or restore the permeability of the formation byrendering the clay contained therein resistant to swelling,.disruption'and/or migration, and also to shrink essentially irreversibly the hydrated, swollen clay which'may be present in said formations adjacent wells producing fluids, such as by drocarbons, water, etc., or in wells which are'used to inject such fiuids into ageologic formation. 'The clay in the formation can be that which was present originally,

use of a clay-containing drilling mud, or in subsequent operations.

The clay originally present in the formation can reduce the permeability of the formation by swelling and/ or migrating to form bridges or blocks in the pores of the formation or in perforations in casing, screens, etc., used in well completions, as a result of contact of said clay with aqueous liquids such as water, certain brines, emulsions containing water or certain brines, etc. This liquid can be introduced into the formation as drilling mud filtrate, injection water, water from leaks in or behind the casing, or ground water associated with the formation. Of particular concern in the case of introduced clay is that clay which, as a component of the drilling mud, invades the formation during the drilling of the borehole. High swelling montmorillonite is often used in drilling muds, among other reasons, because of its ability to create a low permeability filter cake on the formation. Under some conditions, a lowj permeability zone is created within the formation in the vicinity of the borehole from invasion by the drilling mud. In addition, if the mud filter cake is not removed completely when drilling has been completed, it forms a barrier to the flow of fluid into or out from the formation. The invention disclosed and claimed herein will shrink the hydrated, swollen clay in the formation, mud cake, and/ or invaded zone so as to substantially increase the permeability and mechanical and chemical stability of the formation.

Among the clays which may be present originally in natural geological formations or may have been introduced therein and which can be elfectively treated in accordance with the present invention there are included clay minerals of the montmorillonite group such as mont- I morillonite, saponite, nontronite, hectorite, and sauconite; the kaolin group such as kaolinite, nacrite, dickite, and halloysite; the hydrous-mica group such as hydrobiotite, glauconite, illite and bramallite; the chlorite group such as chlorite and chamosite; clay minerals not belonging to the above groups such as vermiculite, attapulgite, and sepiolite; and mixed-layer varieties of the above minerals and groups. The clay content of the formations can be comprised substantially of a single species of clay mineral, or of several species, including the mixed-layer types'of clay. Of the clay minerals commonly encountered in the drilling of wells in natural geological formations which can be productive of the diiliculties herein noted and which can be treated effectively in accordance with the present invention are clay minerals selected from the class consisting of the montmorillonite group, hydrous-mica group, chlorite group, and kaolin group. It will be understood that the clay formations treated in accordance with the invention need not be composed entirely of clay but may contain other mineral components associated therewith.

Clays can swell and/or disperse, disintegrate or otherwise become disrupted in the presence of aqueous fluids. A clay which swells is not limited to expanding latticetype clays but includes all those clays which can increase in bulk volume with or without dispersing, disintegrating or otherwise becoming disrupted when subjected to coniii the presence of such aqueous solutions will expand and be disrupted to the extent that they will become unconsolidated and move into a borehole. Formations which consist largely of clay can develop pressures on the order of 3 several thousand pounds per square inch upon water in a confined space.

The clay materials defined above occur as minute, platelike, tube-like and/or fiber-like particles having an. ex- ,tremely large surface area compared to that of an equivalent quantity of a granular material such as sand. This combination of small size and great surface area results in a high surface energy with attendant unusual surface properties and extreme afiinity for surface-active agents. The structure of some of these clays, asfor instance montmorillonite, can be pictured as a stack of sheet-like three-layer lattice units which are weakly bonded to each other and which are expanded in the c crystallographic direction by water or other substances which can penetrate between the sheets and separate them.

All clay minerals have ion-exchange properties. Thus, for example, montmorillonite has a cation-exchange caabsorbing pacity of from about 90 to 130 milliequivalents per 100 grams of pure clay, illite fromabout 20 to 40 milliequivalents, and kaolinite from about 5 to 15 milliequivalents. Under ordinary oil-well conditions the ion-exchange reactions between the clays and substances associated with the clays and capable of reacting therewith are essentially reversible.

The properties of the clays vary Widely with the cations occupying the base-exchange positions or sites. A baseexchange position or site can be defined as an area, in this instance on a clay crystal, which has associated with it an exchangeable cation. Among the cations which are generally found on the base-exchange position or site can be mentioned sodium, potassium, calcium, magnesium, iron, hydrogen, etc. These cations are believed to be held to the clay surface by ionic forces.

The cations occupying the base-exchange sites on the clay can be those originally present or cations finding their way to the base-exchange position from the liquids in contact therewith. Accordingly, the nature and concentrations of ions in the water in contact with the clay can determine the cations occupying the base exchange sites. In most oil well formations the natural waters associated therewith contain sodium as thepredominant cation, with calcium, magnesium and other cations present in much smaller quantities. Since the base-exchange positions on the clay are occupied by cations, in many cases the cation will be sodium when natural ground waters such as those described above are associated therewith. Unfortunately, however, as for example in the case of the sodium form of montrnorillonite, these clay minerals swell in the presence of Water or certain brines and can, in some instances, exert pressures up to thousands of pounds per square inch. Thus, dependent upon the amount of water absorbed, the clay can change to a rigid paste or a gelatinous mass, or if s'utficient water is present, the clay can disperse completely into the aqueous phase.

I have found that the difficulties noted above can be substantially reduced and a clay body can be stabilized to impart or maintain satisfactory permeability to fluids, improved mechanical strength and increased resistance to chemical attack by treating such clay body with substituted ammonium ions derived brom basic nitrogen compounds represented by the following general formula:

wherein R1 is selected from the class consisting of hydrogen and methyl, ethyl and propyl groups; R is an alkylene group having from 2 to 12 carbon atoms, with the sum of the number of carbon atoms contained in the R groups plus two times the total number of carbon atoms in all R1 groups being at least six; 11 is an integer from 0 to about 100; and A is an anion such as chloride, bromide, iodide, nitrate, lactate, citrate, salicylate, propionate, etc. While the substituted ammonium ions defined above are effective clay-stabilizing agents, the parent basic nitrogen compoufidsfrom whiclfthe substituted ammonium ions are derived have essentiallyinoclay-stabilizing action.

The substituted ammonium ions can be obtained, among other ways, from salts prepared by reacting an appropriate basic nitrogen compoundof the,class described with an acid, preferably one whose anionic component will not form a precipitatewith ions associated with substances such as aqueous fluids withwhich the substituted ammonium salt may comein contact. Thus, ifthe fluids contain a significant concentration of alkaline earth ions, it is inadvisable to employ salts whose anionic component may be sulfate, oxalate,etc., since aprecipitate can result.

Among the compounds which can be employed in preparing the salts are hydrochloric acid, hydrobromic acid, nitric acid, lactic acid, citric acid," salicylic acid, etc., lower fatty acids such as formic, acetic, propionic, etc., and methyl bromide, ethy1 bromide, isopropyl iodide, etc. Among salts which agelsatisfactory for use in accordance with the present ntion are dipropylenetriamine trihydrochloride, uipiq enetriamine 'trihydrobromide, triethylenetetramine "tetrahydrochloride, 3-dirnethylaminopropylamin'e dihydrochloride, 3 dimethylaminopropylamine dinitrate, tetraetliylenepentamine pentahydrochloride, 'tetraethylenepentarnine' pentaacetate, B-isopropylaminopropylamine dihydrochloride, ,3-isopropylaminopropylamine di lactate, 3 -dimethylaminopropylamine dihy drochloride, 3-diethylaihinopropylamine dicitrate, 1,1O-diaminodecane dihydro clilbride, 1,10-diaminodecane disalicylate, Z-aminO S-idiethyIamino entane dihydrochloride, 2-amino-5=diethylarninopentane dipropionate, 1,8-diarninooctane dihydrochloride,1,8-diaminooctane diformate, 1,6-

, diaminohexane dihydrochloride, 1,6-diaminohexane diiodide, N,N- diethylethylene diamine dihydrochloride, N-nbutylpoly-4-vinylpyi idine' bromide, poly-4-vinylpyridine bromide and polyvinylarnine acetate;

'In treating the clay, substituted ammonium ions or mixtures of the substituted ammonium ions dissolved in any suitable polar solvent such as water, methyl alcohol, ethyl alcohol, mixed solvents, .etcl can be employed. The solution employed. ca 'be of any desired concentration, from 'as littleas oneh redth molar to a saturated solution, butpreferably "concentration of about 0.75 to about one andon'e'i alf 'molar.

The amount of. solutionnecessary to treat the clay body and obtain the beneficial resultsof this invention depends on a number" of variables, for example the amount of clay, the concentration Lof the treating solution, the porosity of .th e clay body, the desired depth of penetration into the clay body and the type of clay to be. treated. In general, theclay is contacted with solutions of substituted ammonium ions in such amounts as to provide at least 1,

. and preferably at least 5 milliequivalents of substituted ammonium ions per milliequivalent of base exchange capacityof theclay. .In any case, best results are obtained by using an excess of'substituted ammonium ions, measured as milliequivalents, over the number of base-exchange positions, also measured as milliequivalents, on the clay to be treated.

T o treat the clay with thesolution containing the substituted ammonium ions any suitable method that will assure eflective contact between the solution and the clay can be employed. In treating a formation adjacent a well, for example, the solution containing the substituted ammonium ions can bespotted adjacent the formation or formations to be treatedand then be permitted to permeate the formation, pressure being used to force the solution into the formation if desired. In addition, the solution can be usedtotreat an oil well formation by spotting, priortoshooting, a sufficient amount of the solution in a well'bore adjacent a section to be shot and then shooting. Also, in gun perforating or jet perforating a well, the

solution can be. spottedthrough the interval to be perforated and the gun then inserted and fired in the hole opposite the interval. In secondary recovery, such as a Water flood program, the treating solution can be used in front of the flood to stabilize the clay in the formation as the flood progresses through the formation, thus precluding a drop in injection rate caused by reduced permeability due to swelling and/ or dispersing of the clay. In treating the formation adjacent a borehole of a well which is producing hydrocarbons, the beneficial results of this invention can be obtained by treating the formation with sufiicient of the treating fluid to obtain a penetration of at least one foot and preferably between about and 50 feet, and then returning the well to production.

The mechanism involved in treating clays in accordance with my invention is an ion-exchange reaction between exchangeable cations of the clay and the substituted ammonium ions in the treating solution. When the clay is contacted with the substituted ammonium ions identified above, the substituted ammonium ions exchange quickly and in an essentially irreversible manner with the cations occupying the base-exchange sites on the clay structure. As a result of this treatment, hydrated, swollen clay will shrink essentially irreversibly, unhydrated clay will be rendered insensitive to water and other swelling agents, and the resistance of the clay to mechanical and chemical attack will be increased.

In order to demonstrate the effectiveness of the substituted ammonium ions identified above as clay-stabilizing agents, I have run. a series of tests in which various substituted ammonium ions were employed. The substituted ammonium ions were formed by dissolving in water salts obtained by the reaction of a suitable basic nitrogen compound with hydrochloric acid. Montmorillonite was chosen as the clay for these tests because of its very high ability to swell and disperse. The tests comprised placing 0.077 gram of montmorillonite (0.077 milliequivalent base-exchange capacity) suspended in 5.0 milliliters of a salt solution in a test tube. One liter of the salt solution prior to suspending montmorillonite therein contained 2,317 milligrams of sodium bicarbonate, 279.9 milligrams of calcium chloride hydrate, 434.2 milligrams of magnesium chloride hydrate, and 0.86 milligram of magnesium sulfate. The contents of the test tube were allowed to set for 48 hours, after which the amount of precipitate was measured. The substituted ammonium ion was then added to the contents of the test tube in an amount equal to five times the base-exchange capacity of the clay and the mixture was-shaken for 15 minutes and subsequently allowed to stand for 24 hours. At the end of this period the volume of clay precipitate was estimated and such quantity of supernatant liquid was withdrawn from the test tube that the volume of the liquid and clay remaining was the same as the volume of the clay suspension originally treated. Fifteen milliliters of distilled water were added to the resulting mixture'and the test tube was shaken for 15 minutes and allowed to stand for 24 hours, after which the volume of clay precipitate was again estimated. This cycle was repeated a number of times. At about the 15th test cycle and for one cycle only, a salt solution similar to that in which the montmorillonite was initially dispersed was substituted for the distilled water. Otherwise, the procedure was not changed. Each cycle results in a decrease in the salt concentration of the aqueous solution and the concentration of treating agent in equilibrium with the clay precipitate. This dilution process will cause swelling and/or dispersion of the clay if it has not been efiectively stabilized. The substitution of the original salt solution for the distilled water at about the 15th test cycle is a test for the reversibility of the base-exchange reaction. Thus, if the treating agent is not held essentially irreversibly by the clay, part or all of it will be exchanged for sodium ions or other cations from the salt solution and the clay will swell and disperse in subsequent cycles of distilled Water leaching. 1

The results of these tests are tabulated below in the table.

Table Compound Cycles to Cycles to Colloidal Swelling Appearand/or ance Dispersion Diethylenetriamine trihydrochloride 11 6 1.4-diaminobutane dihydrochloride----- 10 a Ethylenediamine dihydrochloride 6 20 1.2-diarninopropane dihydrochloride 5 20 lflipropylenetriamine trihydrochloride Triethylenetetramine tetrahydrochloride 3dianethylaminopropylamine dihydrochlori e Tetraethylenepcntamine pentahydrochloride 3dmapropylaminopropylamine dihydroch'lor1 e 3 diethylaminopropylamine dihydroohloride N ,N -diphenylethylenediamine dihydrochloride 16 a Llil-diaminodecane dihydrochloride. 2-arr1iino-5-diethylaminopentane dihydrochlo- T1 9 3-dodecylaminopropylamine dihydrochloride 1 8 1,5-diaminopentanc dihydrochloride 15 a 1,8-diaminooctane dihydrochloride. 1,3-diaminopropane dihydrochloride 18 a. 1,3-diaminobutane dihydrochloride. 15 2 1,{3-diaminohexane dihydrochloride. N,N-diethyleth ylcnediamine dihydrochloride- Guanidine hydrochloride 6 a denotes that the test was discontinued at the end of 24 cycles and no swelling. dispersions, or colloidal appearance was noted.

(a) denotes that; the test had a colloidal appearance at the cycle indicated in column A" but had not swelled or dispersed at the end of 24 cye cs.

colloidal condition indicates that the clay has not been.

stabilized by the substituted ammonium ion tested. By swelling it is meant that the settled volume of the clay at the end of 24 hours is at least 1 /2 times the settled volume of the clay at the beginning of the test. By dispersion it is meant that the clay is dispersed uniformly throughout the liquid so that at the end of 24 hours no precipitate or sediment can be detected. Obviously, when the clay swells or disperses it has not been stabilized by the particular substituted ammonium ion tested.

The above table graphically illustrates the advantages of the present invention. Thus, it can be seen that many substituted ammonium ions derived from polybasic nitrogen compounds, e. g., diethylenetriamine tr-ihydrochloride, 1,4-diaminobutane dihydrochloride, ethylenediamine dihydrochloride, 1,2 diaminopropane dihydrochloride, N,N'-diphenylethylenediamine dihydrochloride, 3-dodecylaminopropylamine dihydrochloride, 1,5-diaminopentane dihydrochloride, 1,3-diaminopropane dihydrochloride, 1,3-diaminobutane dihydrochloride, and guanidine hydrochloride, are unsatisfactory as treating agents for stabilizing clays, for clays treated therewith were easily dispersed and resulted in aqueous solutions having a colloidal appearance. Substituted ammonium ions derived from polybasic nitrogen compounds embraced by the generic formulae defined hereinabove, e. g., dipropylenetriarnine trihydrochloride, triethylenetetramine tetrahydrochloride, 3-climethylaminopropylamine dihydrochloride, tetraethylenepentamine pentahydrochloride, 3-isopropylaminopropylamine dihydrochloride, B-diethylaminopropylamine dihydrochloride, 1,10-diaminodecane dihydrochloride, 2-amino-S-diethylaminopentane dihydrochloride, 1,8-diaminooctane dihydrochloride, 1,6-diamin0- hexane dihydrochloride and N,N-diethylethylenediamine dihydrochloride, proved -to-be very effective, for even at the end of 24 cycles the clay treated therewith was unattected by water or the salt solution.

There follow illustrative embodiments of the actual practice of the process of this invention as applied to oil wells producing from formations containing clay. It is understood that the procedures described are illustrative and the invention is not to be limited thereby.

In treating a formation adjacent the bottom of a borehole to stabilize the clay, said formation containing about per cent by weight of montmorillonite and having a porosity of about per cent, so as to attain a radial depth of treatment of at least 5 feet from the borehole, about 150 gallons of a one-molar aqueous solution of substituted ammonium ions derived from B-diethylaminopropylamine dihydrochloride for each foot of vertical thickness of the formation to be treated is used. While theoretically only about 70 gallons of the above treating solution would be needed to react with all of the clay in the above volume of formation, an excess over the theoretical quantity is employed to assure rapid and complete reaction with the clay. The treating solution is introduced through a string of small diameter pipe lowered to within a few feet of the bottom of the hole and allowed to flow in by gravity. Since the treating solution has a much higher specific gravity than water, oil or ordinary oil field brines, it will displace water or oil opposite the formation to be treated and will then flow into the formation. As an aid in displacing the treating solution into the formation, pressure can be employed. The treating solution is introduced into the formation slowly and allowed to remain in contact with the formation for about 24 hours, after which the unused portion, along with produced fluid, is withdrawn from the well. It will be understood that, instead of treat ing formations adjacent the bottom of a borehole, any selected formation interval above the bottom of the borehole can be treated in accordance with the invention by setting a bridge plug, in known manner, at the bottom of the formation to be treated, and thereafter proceeding as described above considering the top of the bridge plug to be the bottom of the borehole.

The process of this invention is also used to advantage in secondary recovery operations wherein a displacement fluid such as water is applied under pressure to an oil-bearing formation by means of specially equipped input wells penetrating said formation for the purpose of forcing the oil out of the oil-bearing formation through an output well penetrating said formation. Such operations are often developed in what is termed a five-spot pattern, with the producing well located in the center of a square formed by water input wells at the four corners. By introducing any of the treating solutions disclosed herein into the water input wells prior to injection of water, the treating solution will move ahead of the advancing water and thus stabilize the clay i in the formation before the clay has had an opportunity to come in contact with the injection water and be deleteriously affected by contact therewith. In actual practice, the treating solution is placed adjacent the formation to be treated by introducing the same through a string of small diameter pipe lowered to a point adjacent the section of the formation to be treated in the manner described in the paragraph next preceding and is followed by normal injection of Water. To establish a front of the treating solution about five feet thick (radially) ahead of the injection water at a radius of about feet from the borehole in a formation having the same montmorillonite content and porosity described above. about 650 gallons of a one-molar aqueous solution of 3-diethylaminopropylamine dihydrochloride is sufficient for each foot of thickness (vertical) of the formation to be treated. Because of prior treatment in accordance with the invention, a satisfactory permeability of the clay during the water flood is maintained or improved, thereby leading to more efficient recovery of the fluids to be produced.

The treating solutions herein disclosed are also employed with advantage in oil-well perforating. When clay-water drilling muds are used in rotary drilling, they seal off the openings in porous formations encountered while drilling. In well completions where such formations are cased off and the casing must be perforated for production, the sealing property of clay-water muds can be detrimental. Since the hydrostatic head of the mud in the borehole exceeds the formation pressure, when the casing is perforated the clay-water mud rushes into the perforated formation until a mud cake seal is established or the pressure is balanced. This often is accompanied by a fresh water loss to the formation, which in the clay formations described, swells the clay which is present. In addition, there often results blocking of the perforated formation to such an extent that on subsequent completion of the well the perforations have to be washed or acidized with reagents known as mud clean out agents.

To avoid such difficulties in perforating operations in accordance with the present invention, a string of tubing is lowered into the borehole so that its lower end is adjacent the bottom of the section to be treated and about 300 gallons of a suitable oil-base drilling fluid is introduced through the tubing to displace the clay-water drilling mud upwardly in the borehole. About gallons of a one-molar aqueous solution of the treating solution, e. g., 3-diethylaminopropylamine dihydrochloride, for each foot of thickness of the formation is thereafter introduced through the tubing and in turn displaces the oil-base drilling fluid upwardly in the borehole. The perforating gun, either bullet or jet, is then lowered into the treating solution opposite the formation to be treated and the casing perforated in the usual manner. The hydrostatic head in the borehole exceeds the formation pressure and thus will force the treating solution into the formation. In this way, the naturallyoccurring clay, which was exposed to fresh water lost to the formation from the clay-water drilling fluid, will be shrunken and stabilized and when the well is permitted to flow, or is swabbed or pumped, the unused claystabilizing agent in the treating solution will be produced from the formation. This operation will leave the formation substantially free from plugging by mud cake or other hydrated clay. Thus, by employing any one of the treating agents disclosed herein while perforating, the formation will be prevented from being mudded olf, the harmful effects of fresh water on naturally-occurring clay will be nullified, the necessity for washing perforations with so-called mud acids will be eliminated, and the use of conventional clay-water drilling muds will be permitted in areas where the producing formations contain swelling-type clays and the more expensive oil-base muds are commonly used.

Similarly in oil well shooting in open hole with high explosives, such as nitroglycerine, trinitrotoluene, etc., the freshly exposed formation may also be contacted with a clay-water drilling fluid with the accompanying harmful effects described above. The drilling fluid opposite the formation to be treated in such case can be replaced with an oil-base drilling fluid followed by the treating solution in the manner described above, and the explosive can be lowered into the solution and detonated in the customary manner. The beneficial results obtained in employing the treating solutions of the invention while perforating will also accompany their use with high explosives.

While I have found that the specific substituted ammonium ions disclosed herein, or mixtures thereof are satisfactory for the purposes of this invention, there are certain instances wherein it is advantageous to employ in admixture therewith other substituted ammonium ions not specifically disclosed herein but which have similar properties thereto, as for example, the substituted ammonium ions disclosed in my copending application filed concurrently herewith, application Serial No. 469,854 as well as in the other concurrently filed applications filed jointly with Clifford R. Giacobine, application Serial Nos. 469,855 to 469,861, inclusive. For example, although by far the greatest portion of the base-exchange sites on a clay mineral surface will have. an. areaapproximating the average area per exchange site, a small number of sites will have an area considerably less than the average. Because of the spatial configuration of their hydrophobic part, certain substituted ammonium ions will not be able to occupy these smaller sites, in which case it is advantageous to use one or more additional substituted ammonium ions of different spatial configuration which can occupy the remaining positions and thus complete the stabilization reaction. It is believed that this use is especially advantageous in the case of the mixed-layer clay minerals.

Obviously, many modifications and variations of the invention, as hereinabove set forth, maybe made Without departing from the spirit and scope thereof, and therefore only such limitations should be imposed. as are indicated in the appended claims.

I'claim:

1. A method of stabilizing a clay-containing body which comprises contacting such clay-containing body with substituted ammonium ions'derived from basic nitrogen compounds represented by the following general formula:

wherein R1 is selected from the class consisting of hydrogen and methyl, ethyl and propyl groups; R is an alkylene group having from 2 to 12 carbon atoms, with the sum of the number of carbon atoms contained in the R groups plus two times the total number of carbon atoms in all R1 groups being at least six; n is an integer from to about 100; and A is an anion.

2. A method of stabilizing a clay-containing body as in claim 1 in which the clay-containing body comprises at least one clay mineral selected from the class consisting of the montmorillonite group, hydrousmica group, chlorite group, and kaolin group.

3. A method of stabilizing a clay-containing body which comprises contacting such clay-containing body with substituted ammonium ions derived from 3-diethylaminopropylamine.

4. A method of stabilizing a clay-containing body which comprises contacting such clay-containing body with substituted ammonium ions derived from 1,10-diarninodecane.

5. A method of stabilizing a clay-containing body which comprises contacting such clay-containing body with substituted ammonium ions derived from triethylenetetramine.

6. A method of stabilizing a which comprises contacting such with substituted ammonium ions aminooctane. v v

7. A method of stabilizing a clay-containing body which comprises contacting such clay-containing body with substituted ammonium ions derived from 3-dimethylaminopropylamine.

8. A method of stabilizing a clay-containing formation adjacent a well bore which comprises contacting such clay-containing formation with substituted ammonium ions derived from basic nitrogen compounds represented by the following general formula:

clay-containing body clay-containing body derived from 1,8-diwherein R1 is selected from the class consisting of hydrogen and methyl, ethyl and propyl groups; R is an alkylene group having from 2 to 12 carbon atoms, with the sum of the number of carbon atoms contained in the R groups plus two times the total number of carbon atoms in all R1 groups being at least six; n is an integer from 0 to about 100; and A is an anion.

9. A method of stabilizing a clay-containing formation adjacent a well bore which comprises contacting such clay containing formation with substituted ammonium. ions derived from 3-diethylaminopropylamine.

10. A method of stabilizing a clay-containing formation adjacent. a well bore which comprises contacting such clay-containing formation with substituted ammonium ions derived from 1,10-diaminodecane.

11. A method of stabilizing a clay-containing, formation adjacent a well bore which comprises contacting such clay-containing formation with substituted ammonium ions derived from triethylenetetramine.

12. A method of stabilizing a clay-containing formation adjacent a well bore which comprises contacting such clay-containing formation with substituted ammonium ions derived from 1,8-diaminooctane.

13. A method of stabilizing a clay-containing formation adjacent a well bore which comprises: contacting such clay-containing formation with substituted ammonium ions derived from 3-dimethylaminopropylamine. Y

14. A method of recovering oil from an oil-bearin formation containing clay, wherein a displacement fluid under pressure is applied to said formation through at least one input well penetrating said formation, and wherein oil is recovered from an output well penetrating said formation, which comprises introducing a treating solution containing substiuted ammonium ions derived from basic nitrogen compounds represented by the followwherein R1 is selected from the class consisting of hydrogen and methyl, ethyl and propyl groups; R is an alkylene group having from 2 to 12 carbon atoms, with the sum of the number of carbon atoms contained in the R groups plus two times the total number of carbon atoms in all R1 groups being at least six; 11 is an integer from 0 to about 100, and A is an anion; into said input well, thereafter introducing said displacement fluid under pressure into said input well, forcing said treating soluing through said formation by means of said displacement fluid, and recovering oil from said output well.

15. A method of recovering oil from an oil-bearing formation containing clay, wherein a displacement fluid under pressure is applied to said formation through at least one input well penetrating said formation, and wherein oil is recovered from an output well penetrating said formation, which comprises introducing a treating solution containing substituted ammonium ions derived from 3-diethylaminopropylamine into said input well, thereafter introducing said displacement fluid under pressure into said input well, forcing said treating solution through said formation by means of said displacement fluid, and recovering oil from said output well.

16. A method of recovering oil from an oil-bearing formation containing clay, wherein a displacement fluid under pressure is applied to said formation through at least one input well penetrating said formation, and wherein oil is recovered from an output well penetrating said formation, which comprises introducing a treating solution containing substituted ammonium ions derived from 1,10-diaminodecane into said input Well, thereafter introducing said displacement fluid under pressure into said input well, forcing said treating solution through said formation by means of said displacement fluid, and recovering oil from said output well.

17. A method of recovering oil from an oil-bearing formation containing clay, wherein a displacement fluid under pressure is applied to said formation through at least one input well penetrating said formation, and wherein oil is recovered from an output well penetrating said formation, which comprises introducing a treating solution containing substituted ammonium ions derived said input well, forcing said treating solution through said 1 formation by means of'said displacement fluid, and recovering oil from said outputwell. 1

18. A method of recovering oil from an oil-bearing formation containing clay, wherein a displacement fluid under pressure is applied to said formation through at least one input well penetrating said formation, and wherein oil is recovered from an output well penetrating said formatiom which comprises introducing a treating solution containing substituted ammonium ions derived from 1,8-diaminooctane into said input well, thereafter introducing said displacement fluid under pressure into said input well, forcing said treating solution through said formation by means of said displacement fluid, and recovering oil from said output W ll,

19. A method of recovering oil from formation containing clay, wherein a, displacement fluid under pressure is applied to said formation through at least one input well penetrating said formation, and where in oil is recoveredfrom an output well penetrating said formation, which 7 comprises introducing a treating solution containing substituted ammonium ions derived from an oil-hearing I S-dimethylaminoprogiylamine into said input well, there- I 1 after introducing said displacement fluid under pressure I into said input well, forcing said treating solution through said formation by means of said displacementfluid, and

recovering oil from said output well.

References; Cited in the file of this patent v UNITED STATES PATENTS 2,262,428 Leitz Nov. 11, 1941 2,320,009 Ralston et a1 May 25, 1943 1 7 2,348,458 Endersby May 9, 1944 2,414,668 Ratcliffe Ian. 21, 1947 2,419,755 Albaugh Apr. 29, 1947 2,472,400 Bond June 7, 1949 2,531,440 "Jordan 1.--. Nov. 28, 1950 2,599,342 Meadors June 3, 1952 2,603,598 Meadors July 15, 1952 2,607,744 I 'Viles Aug. 19, 1952 2,659,693 Lytle Nov; 17, 1953 2,681,314 Skinner June 14, 1954 FOREIGN PATENTS, a

881,982 Germany July 9, 1953 

1. A METHOD OF STABILIZING A CLAY-CONTAINING BODY WHICH COMPRISES CONTACTING SUCH CLAY-CONTAINING BODY WITH SUBSTITUTED AMMONIUM IONS DERIVED FROM BASIC NITROGEN COMPOUNDS REPRESENTED BY THE FOLLOWING GENERAL FORMULA: 